Development of a platform to investigate long-term potentiation in human iPSC-derived neuronal networks.

Impairment of long-term potentiation (LTP) is a common feature of many pre-clinical models of neurological disorders; however, studies in humans are limited by the inaccessibility of the brain. Human induced pluripotent stem cells (hiPSCs) provide a unique opportunity to study LTP in disease-specific genetic backgrounds. Here we describe a multi-electrode array (MEA)-based assay to investigate chemically induced LTP (cLTP) across entire networks of hiPSC-derived midbrain dopaminergic (DA) and cortical neuronal populations that lasts for days, allowing studies of the late phases of LTP and enabling detection of associated molecular changes. We show that cLTP on midbrain DA neuronal networks is largely independent of the N-methyl-D-aspartate receptor (NMDAR) and partially dependent on brain-derived neurotrophic factor (BDNF). Finally, we describe activity-regulated gene expression induced by cLTP. This cLTP-MEA assay platform will enable phenotype discovery and higher-throughput analyses of synaptic plasticity on hiPSC-derived neurons.

The conserved MASRPF motif in the Attractin homolog, Distracted, is required for association with Drosophila E3-ligase Mgrn1.

In rodents, all three paralogs of the Attractin (Atrn) transmembrane protein family exhibit strong phenotypic overlap and are implicated in the regulation of the same G-protein coupled receptors (GPCR) as E3-ligase Mahogunin ring finger 1 (Mgrn1). Recently it was shown that the highly conserved intracellular MASRPF motif in mammal Multiple epidermal growth factor-like domain 8 protein is required for binding of Mgrn1 to mediate ubiquitination of GPCR Smoothened in vitro. Here, we show that the MASRPF motif of Drosophila Distracted, the ortholog of ATRN and Attractin-like 1, is required for association with Drosophila Mgrn1 (dMgrn1) in vivo.

Transcriptional dysregulation by a nucleus-localized aminoacyl-tRNA synthetase associated with Charcot-Marie-Tooth neuropathy.

Charcot-Marie-Tooth disease (CMT) is a length-dependent peripheral neuropathy. The aminoacyl-tRNA synthetases constitute the largest protein family implicated in CMT. Aminoacyl-tRNA synthetases are predominantly cytoplasmic, but are also present in the nucleus. Here we show that a nuclear function of tyrosyl-tRNA synthetase (TyrRS) is implicated in a Drosophila model of CMT. CMT-causing mutations in TyrRS induce unique conformational changes, which confer capacity for aberrant interactions with transcriptional regulators in the nucleus, leading to transcription factor E2F1 hyperactivation. Using neuronal tissues, we reveal a broad transcriptional regulation network associated with wild-type TyrRS expression, which is disturbed when a CMT-mutant is expressed. Pharmacological inhibition of TyrRS nuclear entry with embelin reduces, whereas genetic nuclear exclusion of mutant TyrRS prevents hallmark phenotypes of CMT in the Drosophila model. These data highlight that this translation factor may contribute to transcriptional regulation in neurons, and suggest a therapeutic strategy for CMT.

A single pair of leucokinin neurons are modulated by feeding state and regulate sleep-metabolism interactions.

Dysregulation of sleep and feeding has widespread health consequences. Despite extensive epidemiological evidence for interactions between sleep and metabolic function, little is known about the neural or molecular basis underlying the integration of these processes. D. melanogaster potently suppress sleep in response to starvation, and powerful genetic tools allow for mechanistic investigation of sleep-metabolism interactions. We have previously identified neurons expressing the neuropeptide leucokinin (Lk) as being required for starvation-mediated changes in sleep. Here, we demonstrate an essential role for Lk neuropeptide in metabolic regulation of sleep. The activity of Lk neurons is modulated by feeding, with reduced activity in response to glucose and increased activity under starvation conditions. Both genetic silencing and laser-mediated microablation localize Lk-dependent sleep regulation to a single pair of Lk neurons within the Lateral Horn (LHLK neurons). A targeted screen identified a role for 5' adenosine monophosphate-activated protein kinase (AMPK) in starvation-modulated changes in sleep. Knockdown of AMPK in Lk neurons suppresses sleep and increases LHLK neuron activity in fed flies, phenocopying the starvation state. Further, we find a requirement for the Lk receptor in the insulin-producing cells (IPCs), suggesting LHLK-IPC connectivity is critical for sleep regulation under starved conditions. Taken together, these findings localize feeding-state-dependent regulation of sleep to a single pair of neurons within the fruit fly brain and provide a system for investigating the cellular basis of sleep-metabolism interactions.

An ankyrin-binding motif regulates nuclear levels of L1-type neuroglian and expression of the oncogene Myc in Drosophila neurons.

L1 cell adhesion molecule (L1CAM) is well-known for its importance in nervous system development and cancer progression. In addition to its role as a plasma membrane protein in cytoskeletal organization, recent in vitro studies have revealed that both transmembrane and cytosolic fragments of proteolytically cleaved vertebrate L1CAM translocate to the nucleus. In vitro studies indicate that nuclear L1CAM affects genes with functions in DNA post-replication repair, cell cycle control, and cell migration and differentiation, but its in vivo role and how its nuclear levels are regulated is less well-understood. Here, we report that mutations in the conserved ankyrin-binding domain affect nuclear levels of the sole Drosophila homolog neuroglian (Nrg) and that it also has a noncanonical role in regulating transcript levels of the oncogene Myc in the adult nervous system. We further show that altered nuclear levels of Nrg correlate with altered transcript levels of Myc in neurons, similar to what has been reported for human glioblastoma stem cells. However, whereas previous in vitro studies suggest that increased nuclear levels of L1CAM promote tumor cell survival, we found here that elevated levels of nuclear Nrg in neurons are associated with increased sensitivity to oxidative stress and reduced life span of adult animals. We therefore conclude that these findings are of potential relevance to the management of neurodegenerative diseases associated with oxidative stress and cancer.

Lissencephaly-1 dependent axonal retrograde transport of L1-type CAM Neuroglian in the adult drosophila central nervous system.

Here, we established the Drosophila Giant Fiber neurons (GF) as a novel model to study axonal trafficking of L1-type Cell Adhesion Molecules (CAM) Neuroglian (Nrg) in the adult CNS using live imaging. L1-type CAMs are well known for their importance in nervous system development and we previously demonstrated a role for Nrg in GF synapse formation. However, in the adult they have also been implicated in synaptic plasticity and regeneration. In addition, to its canonical role in organizing cytoskeletal elements at the plasma membrane, vertebrate L1CAM has also been shown to regulate transcription indirectly as well as directly via its import to the nucleus. Here, we intend to determine if the sole L1CAM homolog Nrg is retrogradley transported and thus has the potential to relay signals from the synapse to the soma. Live imaging of c-terminally tagged Nrg in the GF revealed that there are at least two populations of retrograde vesicles that differ in speed, and either move with consistent or varying velocity. To determine if endogenous Nrg is retrogradely transported, we inhibited two key regulators, Lissencephaly-1 (Lis1) and Dynactin, of the retrograde motor protein Dynein. Similar to previously described phenotypes for expression of poisonous subunits of Dynactin, we found that developmental knock down of Lis1 disrupted GF synaptic terminal growth and that Nrg vesicles accumulated inside the stunted terminals in both mutant backgrounds. Moreover, post mitotic Lis1 knock down in mature GFs by either RNAi or Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) induced mutations, resulted in normal length terminals with fully functional GF synapses which also exhibited severe accumulation of endogenous Nrg vesicles. Thus, our data suggests that accumulation of Nrg vesicles is due to failure of retrograde transport rather than a failure of terminal development. Together with the finding that post mitotic knock down of Lis1 also disrupted retrograde transport of tagged Nrg vesicles in GF axons, it demonstrates that endogenous Nrg protein is transported from the synapse to the soma in the adult central nervous system in a Lis1-dependent manner.

Input-specific regulation of hippocampal circuit maturation by non-muscle myosin IIB.

Myh9 and Myh10, which encode two major isoforms of non-muscle myosin II expressed in the brain, have emerged as risk factors for developmental brain disorders. Myosin II motors regulate neuronal cytoskeletal dynamics leading to optimization of synaptic plasticity and memory formation. However, the role of these motor complexes in brain development remains poorly understood. Here, we disrupted the in vivo expression of Myh9 and/or Myh10 in developing hippocampal neurons to determine how these motors contribute to circuit maturation in this brain area important for cognition. We found that Myh10 ablation in early postnatal, but not mature, CA1 pyramidal neurons reduced excitatory synaptic function in the Schaffer collateral pathway, whereas more distal inputs to CA1 neurons were relatively unaffected. Myh10 ablation in young neurons also selectively impaired the elongation of oblique dendrites that receive Schaffer collateral inputs, whereas the structure of distal dendrites was normal. We observed normal spine density and spontaneous excitatory currents in these neurons, indicating that Myh10 KO impaired proximal pathway synaptic maturation through disruptions to dendritic development rather than post-synaptic strength or spine morphogenesis. To address possible redundancy and/or compensation by other Myosin II motors expressed in neurons, we performed similar experiments in Myh9 null neurons. In contrast to findings in Myh10 mutants, evoked synaptic function in young Myh9 KO hippocampal neurons was normal. Data obtained from double Myh9/Myh10 KO neurons largely resembled the MyH10 KO synaptic phenotype. These data indicate that Myosin IIB is a key molecular factor that guides input-specific circuit maturation in the developing hippocampus. Non-muscle myosin II is an actin binding protein with three isoforms in the brain (IIA, IIB and IIC) encoded by the myh9, myh10, and myh14 genes in mice, respectively. We have studied the structure and the function of hippocampal CA1 neurons missing NMIIB and/or NMIIA proteins at different times during development. We have discovered that NMIIB is the major isoform regulating Schaffer collateral inputs, and that this regulation is restricted to early postnatal development.

Economic Analysis of Kiva VCF Treatment System Compared to Balloon Kyphoplasty Using Randomized Kiva Safety and Effectiveness Trial (KAST) Data.

BACKGROUND: Vertebral compression fractures (VCFs) are the most common osteoporotic fractures and cause persistent pain, kyphotic deformity, weight loss, depression, reduced quality of life, and even death. Current surgical approaches for the treatment of VCF include vertebroplasty (VP) and balloon kyphoplasty (BK). The Kiva® VCF Treatment System (Kiva System) is a next-generation alternative surgical intervention in which a percutaneously introduced nitinol Osteo Coil guidewire is advanced through a deployment cannula and subsequently a PEEK Implant is implanted incrementally and fully coiled in the vertebral body. The Kiva System's effectiveness for the treatment of VCF has been evaluated in a large randomized controlled trial, the Kiva Safety and Effectiveness Trial (KAST). The Kiva System was non-inferior to BK with respect to pain reduction (70.8% vs. 71.8% in Visual Analogue Scale) and physical function restoration (38.1 % vs. 42.2% reduction in Oswestry Disability Index) while using less bone cement. The economic impact of the Kiva system has yet to be analyzed. OBJECTIVE: To analyze hospital resource use and costs of the Kiva System over 2 years for the treatment of VCF compared to BK. SETTING: A representative US hospital. STUDY DESIGN: Economic analysis of the KAST randomized trial, focusing on hospital resource use and costs. METHODS: The analysis was conducted from a hospital perspective and utilized clinical data from KAST as well as unit-cost data from the published literature. The cost of initial VCF surgery, reoperation cost, device market cost, and other medical costs were compared between the Kiva System and BK. The relative risk reduction rate in adjacent-level fracture with Kiva [31.6% (95% CI: -22.5%, 61.9%)] demonstrated in KAST was used in this analysis. RESULTS: With 304 vertebral augmentation procedures performed in a representative U.S. hospital over 2 years, the Kiva System will produce a direct medical cost savings of $1,118 per patient and $280,876 per hospital. This cost saving with the Kiva System was attributable to 19 reduced adjacent-level fractures with the Kiva System. LIMITATIONS: This study does not compare the Kiva System with VP or any other non-surgical procedures for the treatment of VCF. CONCLUSION: This first-ever economic analysis of the KAST data showed that the Kiva System for vertebral augmentation is hospital resource and cost saving over BK in a hospital setting over 2 years. These savings are attributable to reduced risk of developing adjacent-level fractures with the Kiva System compared to BK.

Proliferative epithelial disease identified in nipple aspirate fluid and risk of developing breast cancer: a systematic review.

BACKGROUND: Guideline panels recognize the need to increase the accuracy of identifying women at high risk of developing breast cancer who would benefit from prevention strategies. The characterization of proliferative epithelial disease found in nipple aspirate fluid (PED-NAF) may be a relevant risk factor. OBJECTIVE: To comprehensively review the published literature to characterize and summarize abnormal cytology detected by NAF and the association of PED-NAF with subsequent risk of developing breast cancer. RESEARCH DESIGN AND METHODS: Literature identified by systematic searches in MEDLINE PubMed and the Cochrane Library was screened for articles containing primary data on NAF cytology based on predefined inclusion and exclusion criteria. MAIN OUTCOME MEASURES: Study characteristics, cytological group distribution, and incidence of breast cancer. RESULTS: Thirty articles were included after full-text review, of which 16 were analyzed, containing data on 20,808 unique aspirations from over 17,378 subjects. Seven (44%) of the studies used the King cytological classification system. Among aspirations from women free of breast cancer, 51.5% contained fluid, in which over 27.7% had PED on cytology. In the two prospective studies of 7850 cancer-free women, abnormal cytology by NAF carried a 2.1-fold higher risk (95% CI, 1.6-2.6; p < 0.001) of developing breast cancer, compared with women from whom no fluid could be obtained. CONCLUSIONS: PED-NAF among women free of breast cancer, compared with no fluid being obtained, has an independent risk of developing breast cancer comparable to the risk of a woman with a positive family history of breast cancer. These findings have implications for augmenting risk prediction and clinical decisions concerning breast cancer surveillance and chemoprevention. As with all reviews, heterogeneity across studies may have influenced the results. The limited literature calls for prospective studies on asymptomatic women with long-term follow-up.

Kv7 potassium channels in airway smooth muscle cells: signal transduction intermediates and pharmacological targets for bronchodilator therapy.

Expression and function of Kv7 (KCNQ) voltage-activated potassium channels in guinea pig and human airway smooth muscle cells (ASMCs) were investigated by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), patch-clamp electrophysiology, and precision-cut lung slices. qRT-PCR revealed expression of multiple KCNQ genes in both guinea pig and human ASMCs. Currents with electrophysiological and pharmacological characteristics of Kv7 currents were measured in freshly isolated guinea pig and human ASMCs. In guinea pig ASMCs, Kv7 currents were significantly suppressed by application of the bronchoconstrictor agonists methacholine (100 nM) or histamine (30 µM), but current amplitudes were restored by addition of a Kv7 channel activator, flupirtine (10 µM). Kv7 currents in guinea pig ASMCs were also significantly enhanced by another Kv7.2-7.5 channel activator, retigabine, and by celecoxib and 2,5-dimethyl celecoxib. In precision-cut human lung slices, constriction of airways by histamine was significantly reduced in the presence of flupirtine. Kv7 currents in both guinea pig and human ASMCs were inhibited by the Kv7 channel blocker XE991. In human lung slices, XE991 induced robust airway constriction, which was completely reversed by addition of the calcium channel blocker verapamil. These findings suggest that Kv7 channels in ASMCs play an essential role in the regulation of airway diameter and may be targeted pharmacologically to relieve airway hyperconstriction induced by elevated concentrations of bronchoconstrictor agonists.

A pharmacoepidemiologic analysis of the impact of calendar packaging on adherence to self-administered medications for long-term use.

BACKGROUND: Calendar blister packaging (CBP) that incorporates a day or date feature is a simple medication packaging technology that is designed to improve medication adherence and persistence. OBJECTIVE: This study was conducted to assess the effect of a new calendar packaging technology on prescription refill adherence and persistence for daily, self-administered, long-term medication use. METHODS: Anonymized pharmacy dispensing data from a large US mass merchandiser were analyzed. This retrospective cohort study included people aged 18 to 75 years who filled prescriptions for oral lisinopril or enalapril (control group) at a study pharmacy during 1 year before and after the switch of lisinopril packaging from vials to CBP. Cohorts were stratified into new and prevalent medication users. We used linear and logistic regression modeling and propensity score matching to assess the impact of CBP on refill adherence, using medication possession ratio (MPR) and proportion of days covered (PDC), and persistence using length of therapy (LOT). RESULTS: Our sample comprised 76,321 new users and 249,040 prevalent users. Across all user, medication, and packaging groups, the mean unadjusted LOT decreased in the follow-up year, possibly due to economic recession. The LOT decline was attenuated in the CBP cohort. After adjustment for covariates, CBP use in new and prevalent medication users was associated with significantly higher LOT and PDC but not MPR. The odds of achieving PDC ≥80% were higher by 15% in new users (odds ratio [OR] = 1.15; 95% CI, 1.09-1.21) and 12% in prevalent users (OR = 1.12; 95% CI, 1.09-1.15) who switched to CBP, compared with continued vial use. CONCLUSIONS: CBP of medication prescribed for daily, self-administered, long-term use was associated with modest improvement in prescription refill adherence and persistence. An adherence strategy of even small effect size that is broadly implemented on a population level could significantly leverage therapeutic effect and provide substantial cumulative public health benefit. Clinical benefit, or harm, associated with use of CBP should be investigated. Usability assessments of CBP in patient subgroups may provide insight about differential impact on adherence and persistence.

Does packaging with a calendar feature improve adherence to self-administered medication for long-term use? A systematic review.

BACKGROUND: The therapeutic benefit of self-administered medications for long-term use is limited by an average 50% nonadherence rate. Patient forgetfulness is a common factor in unintentional nonadherence. Unit-of-use packaging that incorporates a simple day-and-date feature (calendar packaging) is designed to improve adherence by prompting patients to maintain the prescribed dosing schedule. OBJECTIVE: To review systematically, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, randomized controlled trial evidence of the adherence benefits and harms of calendar blister packaging (CBP) and calendar pill organizers (CPO) for self-administered, long-term medication use. METHODS: Data sources included the MEDLINE and Web of Science and Cochrane Library databases from their inception to September 2010 and communication with researchers in the field. Key search terms included blister-calendar pack, blister pack, drug packaging, medication adherence, medication compliance, medication compliance devices, medication containers, medication organizers, multicompartment compliance aid, persistence, pill-box organizers, prescription refill, randomized controlled trials, and refill compliance. Selected studies had an English-language title; a randomized controlled design; medication packaged in CBP or CPO; a requirement of solid, oral medication self-administered daily for longer than 1 month in community-dwelling adults; and at least 1 quantitative outcome measure of adherence. Two reviewers extracted data independently on study design, sample size, type of intervention and control, and outcomes. RESULTS: Ten trials with a total of 1045 subjects met the inclusion criteria, and 9 also examined clinical outcomes (seizures, blood pressure, psychiatric symptoms) or health care resource utilization. Substantial heterogeneity among trials precluded meta-analysis. In 3 studies, calendar packaging was part of a multicomponent adherence intervention. Six of 10 trials reported higher adherence, but it was associated with clinically significant improvement in only 1 study: 50% decreased seizure frequency with a CPO-based, multicomponent intervention. No study reported sufficient information to examine conclusively potential harms related to calendar packaging. LIMITATIONS: All trials had significant methodological limitations, such as inadequate randomization or blinding, or reported insufficient information regarding enrolled subjects and attrition, which resulted in a moderate-to-high risk of bias and, in 2 studies, unevaluable outcome data. Trials were generally short and sample sizes small, with heterogeneous adherence outcome measures. CONCLUSIONS: Calendar packaging, especially in combination with education and reminder strategies, may improve medication adherence. Methodological limitations preclude definitive conclusions about the effect size of adherence and clinical benefits or harms associated with CBP and CPO. High-quality trials of adequate size and duration are needed to assess the clinical effectiveness of such interventions.